* [PATCH net-next 1/4] ipv4: remove fib_devindex_hashfn()
2024-10-04 13:47 [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL Eric Dumazet
@ 2024-10-04 13:47 ` Eric Dumazet
2024-10-04 22:32 ` Kuniyuki Iwashima
2024-10-04 13:47 ` [PATCH net-next 2/4] ipv4: use rcu in ip_fib_check_default() Eric Dumazet
` (4 subsequent siblings)
5 siblings, 1 reply; 13+ messages in thread
From: Eric Dumazet @ 2024-10-04 13:47 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: David Ahern, Kuniyuki Iwashima, Alexandre Ferrieux, netdev,
eric.dumazet, Eric Dumazet
fib_devindex_hashfn() converts a 32bit ifindex value to a 8bit hash.
It makes no sense doing this from fib_info_hashfn() and
fib_find_info_nh().
It is better to keep as many bits as possible to let
fib_info_hashfn_result() have better spread.
Only fib_info_devhash_bucket() needs to make this operation,
we can 'inline' trivial fib_devindex_hashfn() in it.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/fib_semantics.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 1a847ba4045876c91948bcec45cb5eccc0ef1f31..1219d1b325910322dd978f3962a4cafa8e8db10b 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -322,17 +322,12 @@ static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
return 0;
}
-static inline unsigned int fib_devindex_hashfn(unsigned int val)
-{
- return hash_32(val, DEVINDEX_HASHBITS);
-}
-
static struct hlist_head *
fib_info_devhash_bucket(const struct net_device *dev)
{
u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
- return &fib_info_devhash[fib_devindex_hashfn(val)];
+ return &fib_info_devhash[hash_32(val, DEVINDEX_HASHBITS)];
}
static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
@@ -362,10 +357,10 @@ static inline unsigned int fib_info_hashfn(struct fib_info *fi)
fi->fib_priority);
if (fi->nh) {
- val ^= fib_devindex_hashfn(fi->nh->id);
+ val ^= fi->nh->id;
} else {
for_nexthops(fi) {
- val ^= fib_devindex_hashfn(nh->fib_nh_oif);
+ val ^= nh->fib_nh_oif;
} endfor_nexthops(fi)
}
@@ -380,7 +375,7 @@ static struct fib_info *fib_find_info_nh(struct net *net,
struct fib_info *fi;
unsigned int hash;
- hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
+ hash = fib_info_hashfn_1(cfg->fc_nh_id,
cfg->fc_protocol, cfg->fc_scope,
(__force u32)cfg->fc_prefsrc,
cfg->fc_priority);
--
2.47.0.rc0.187.ge670bccf7e-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH net-next 1/4] ipv4: remove fib_devindex_hashfn()
2024-10-04 13:47 ` [PATCH net-next 1/4] ipv4: remove fib_devindex_hashfn() Eric Dumazet
@ 2024-10-04 22:32 ` Kuniyuki Iwashima
0 siblings, 0 replies; 13+ messages in thread
From: Kuniyuki Iwashima @ 2024-10-04 22:32 UTC (permalink / raw)
To: edumazet
Cc: alexandre.ferrieux, davem, dsahern, eric.dumazet, kuba, kuniyu,
netdev, pabeni
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 4 Oct 2024 13:47:17 +0000
> fib_devindex_hashfn() converts a 32bit ifindex value to a 8bit hash.
>
> It makes no sense doing this from fib_info_hashfn() and
> fib_find_info_nh().
>
> It is better to keep as many bits as possible to let
> fib_info_hashfn_result() have better spread.
>
> Only fib_info_devhash_bucket() needs to make this operation,
> we can 'inline' trivial fib_devindex_hashfn() in it.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH net-next 2/4] ipv4: use rcu in ip_fib_check_default()
2024-10-04 13:47 [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL Eric Dumazet
2024-10-04 13:47 ` [PATCH net-next 1/4] ipv4: remove fib_devindex_hashfn() Eric Dumazet
@ 2024-10-04 13:47 ` Eric Dumazet
2024-10-04 22:39 ` Kuniyuki Iwashima
2024-10-04 13:47 ` [PATCH net-next 3/4] ipv4: remove fib_info_lock Eric Dumazet
` (3 subsequent siblings)
5 siblings, 1 reply; 13+ messages in thread
From: Eric Dumazet @ 2024-10-04 13:47 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: David Ahern, Kuniyuki Iwashima, Alexandre Ferrieux, netdev,
eric.dumazet, Eric Dumazet
fib_info_devhash[] is not resized in fib_info_hash_move().
fib_nh structs are already freed after an rcu grace period.
This will allow to remove fib_info_lock in the following patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/fib_semantics.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 1219d1b325910322dd978f3962a4cafa8e8db10b..e0ffb4ffd95d0f9ebc796c3129bc2f494fb478dd 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -275,7 +275,7 @@ void fib_release_info(struct fib_info *fi)
change_nexthops(fi) {
if (!nexthop_nh->fib_nh_dev)
continue;
- hlist_del(&nexthop_nh->nh_hash);
+ hlist_del_rcu(&nexthop_nh->nh_hash);
} endfor_nexthops(fi)
}
/* Paired with READ_ONCE() from fib_table_lookup() */
@@ -431,28 +431,23 @@ static struct fib_info *fib_find_info(struct fib_info *nfi)
}
/* Check, that the gateway is already configured.
- * Used only by redirect accept routine.
+ * Used only by redirect accept routine, under rcu_read_lock();
*/
int ip_fib_check_default(__be32 gw, struct net_device *dev)
{
struct hlist_head *head;
struct fib_nh *nh;
- spin_lock(&fib_info_lock);
-
head = fib_info_devhash_bucket(dev);
- hlist_for_each_entry(nh, head, nh_hash) {
+ hlist_for_each_entry_rcu(nh, head, nh_hash) {
if (nh->fib_nh_dev == dev &&
nh->fib_nh_gw4 == gw &&
!(nh->fib_nh_flags & RTNH_F_DEAD)) {
- spin_unlock(&fib_info_lock);
return 0;
}
}
- spin_unlock(&fib_info_lock);
-
return -1;
}
@@ -1606,7 +1601,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
if (!nexthop_nh->fib_nh_dev)
continue;
head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
- hlist_add_head(&nexthop_nh->nh_hash, head);
+ hlist_add_head_rcu(&nexthop_nh->nh_hash, head);
} endfor_nexthops(fi)
}
spin_unlock_bh(&fib_info_lock);
--
2.47.0.rc0.187.ge670bccf7e-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread* [PATCH net-next 3/4] ipv4: remove fib_info_lock
2024-10-04 13:47 [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL Eric Dumazet
2024-10-04 13:47 ` [PATCH net-next 1/4] ipv4: remove fib_devindex_hashfn() Eric Dumazet
2024-10-04 13:47 ` [PATCH net-next 2/4] ipv4: use rcu in ip_fib_check_default() Eric Dumazet
@ 2024-10-04 13:47 ` Eric Dumazet
2024-10-04 22:41 ` Kuniyuki Iwashima
2024-10-04 13:47 ` [PATCH net-next 4/4] ipv4: remove fib_info_devhash[] Eric Dumazet
` (2 subsequent siblings)
5 siblings, 1 reply; 13+ messages in thread
From: Eric Dumazet @ 2024-10-04 13:47 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: David Ahern, Kuniyuki Iwashima, Alexandre Ferrieux, netdev,
eric.dumazet, Eric Dumazet
After the prior patch, fib_info_lock became redundant
because all of its users are holding RTNL.
BH protection is not needed.
Remove the READ_ONCE()/WRITE_ONCE() annotations around fib_info_cnt,
since it is protected by RTNL.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/fib_semantics.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index e0ffb4ffd95d0f9ebc796c3129bc2f494fb478dd..ece779bfb8f6bec67eb7751761df9a4f158020a8 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -50,7 +50,6 @@
#include "fib_lookup.h"
-static DEFINE_SPINLOCK(fib_info_lock);
static struct hlist_head *fib_info_hash;
static struct hlist_head *fib_info_laddrhash;
static unsigned int fib_info_hash_size;
@@ -260,12 +259,11 @@ EXPORT_SYMBOL_GPL(free_fib_info);
void fib_release_info(struct fib_info *fi)
{
- spin_lock_bh(&fib_info_lock);
+ ASSERT_RTNL();
if (fi && refcount_dec_and_test(&fi->fib_treeref)) {
hlist_del(&fi->fib_hash);
- /* Paired with READ_ONCE() in fib_create_info(). */
- WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
+ fib_info_cnt--;
if (fi->fib_prefsrc)
hlist_del(&fi->fib_lhash);
@@ -282,7 +280,6 @@ void fib_release_info(struct fib_info *fi)
WRITE_ONCE(fi->fib_dead, 1);
fib_info_put(fi);
}
- spin_unlock_bh(&fib_info_lock);
}
static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
@@ -1266,7 +1263,7 @@ static void fib_info_hash_move(struct hlist_head *new_info_hash,
unsigned int old_size = fib_info_hash_size;
unsigned int i;
- spin_lock_bh(&fib_info_lock);
+ ASSERT_RTNL();
old_info_hash = fib_info_hash;
old_laddrhash = fib_info_laddrhash;
fib_info_hash_size = new_size;
@@ -1303,8 +1300,6 @@ static void fib_info_hash_move(struct hlist_head *new_info_hash,
}
}
- spin_unlock_bh(&fib_info_lock);
-
kvfree(old_info_hash);
kvfree(old_laddrhash);
}
@@ -1380,6 +1375,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
int nhs = 1;
struct net *net = cfg->fc_nlinfo.nl_net;
+ ASSERT_RTNL();
if (cfg->fc_type > RTN_MAX)
goto err_inval;
@@ -1422,8 +1418,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
err = -ENOBUFS;
- /* Paired with WRITE_ONCE() in fib_release_info() */
- if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
+ if (fib_info_cnt >= fib_info_hash_size) {
unsigned int new_size = fib_info_hash_size << 1;
struct hlist_head *new_info_hash;
struct hlist_head *new_laddrhash;
@@ -1582,7 +1577,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
refcount_set(&fi->fib_treeref, 1);
refcount_set(&fi->fib_clntref, 1);
- spin_lock_bh(&fib_info_lock);
+
fib_info_cnt++;
hlist_add_head(&fi->fib_hash,
&fib_info_hash[fib_info_hashfn(fi)]);
@@ -1604,7 +1599,6 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
hlist_add_head_rcu(&nexthop_nh->nh_hash, head);
} endfor_nexthops(fi)
}
- spin_unlock_bh(&fib_info_lock);
return fi;
err_inval:
--
2.47.0.rc0.187.ge670bccf7e-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH net-next 3/4] ipv4: remove fib_info_lock
2024-10-04 13:47 ` [PATCH net-next 3/4] ipv4: remove fib_info_lock Eric Dumazet
@ 2024-10-04 22:41 ` Kuniyuki Iwashima
0 siblings, 0 replies; 13+ messages in thread
From: Kuniyuki Iwashima @ 2024-10-04 22:41 UTC (permalink / raw)
To: edumazet
Cc: alexandre.ferrieux, davem, dsahern, eric.dumazet, kuba, kuniyu,
netdev, pabeni
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 4 Oct 2024 13:47:19 +0000
> After the prior patch, fib_info_lock became redundant
> because all of its users are holding RTNL.
>
> BH protection is not needed.
>
> Remove the READ_ONCE()/WRITE_ONCE() annotations around fib_info_cnt,
> since it is protected by RTNL.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH net-next 4/4] ipv4: remove fib_info_devhash[]
2024-10-04 13:47 [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL Eric Dumazet
` (2 preceding siblings ...)
2024-10-04 13:47 ` [PATCH net-next 3/4] ipv4: remove fib_info_lock Eric Dumazet
@ 2024-10-04 13:47 ` Eric Dumazet
2024-10-04 22:45 ` Kuniyuki Iwashima
2024-10-07 14:08 ` Simon Horman
2024-10-04 14:35 ` [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL David Ahern
2024-10-08 0:10 ` patchwork-bot+netdevbpf
5 siblings, 2 replies; 13+ messages in thread
From: Eric Dumazet @ 2024-10-04 13:47 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: David Ahern, Kuniyuki Iwashima, Alexandre Ferrieux, netdev,
eric.dumazet, Eric Dumazet
Upcoming per-netns RTNL conversion needs to get rid
of shared hash tables.
fib_info_devhash[] is one of them.
It is unclear why we used a hash table, because
a single hlist_head per net device was cheaper and scalable.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
.../networking/net_cachelines/net_device.rst | 1 +
include/linux/netdevice.h | 2 ++
net/ipv4/fib_semantics.c | 35 ++++++++-----------
3 files changed, 18 insertions(+), 20 deletions(-)
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index 22b07c814f4a4575d255fdf472d07c549536e543..a8e2a7ce0383343464800be8db31aeddd791f086 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst
@@ -83,6 +83,7 @@ unsigned_int allmulti
bool uc_promisc
unsigned_char nested_level
struct_in_device* ip_ptr read_mostly read_mostly __in_dev_get
+struct hlist_head fib_nh_head
struct_inet6_dev* ip6_ptr read_mostly read_mostly __in6_dev_get
struct_vlan_info* vlan_info
struct_dsa_port* dsa_ptr
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 4d20c776a4ff3d0e881b8d9b99901edb35f66da2..cda20a3fe1adf54c1e6df5b5a8882ef7830e1b46 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2209,6 +2209,8 @@ struct net_device {
/* Protocol-specific pointers */
struct in_device __rcu *ip_ptr;
+ struct hlist_head fib_nh_head;
+
#if IS_ENABLED(CONFIG_VLAN_8021Q)
struct vlan_info __rcu *vlan_info;
#endif
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index ece779bfb8f6bec67eb7751761df9a4f158020a8..d2cee5c314f5e76530ac564f49b433822bb0a272 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -56,10 +56,6 @@ static unsigned int fib_info_hash_size;
static unsigned int fib_info_hash_bits;
static unsigned int fib_info_cnt;
-#define DEVINDEX_HASHBITS 8
-#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
-static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
-
/* for_nexthops and change_nexthops only used when nexthop object
* is not set in a fib_info. The logic within can reference fib_nh.
*/
@@ -319,12 +315,9 @@ static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
return 0;
}
-static struct hlist_head *
-fib_info_devhash_bucket(const struct net_device *dev)
+static struct hlist_head *fib_nh_head(struct net_device *dev)
{
- u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
-
- return &fib_info_devhash[hash_32(val, DEVINDEX_HASHBITS)];
+ return &dev->fib_nh_head;
}
static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
@@ -435,11 +428,11 @@ int ip_fib_check_default(__be32 gw, struct net_device *dev)
struct hlist_head *head;
struct fib_nh *nh;
- head = fib_info_devhash_bucket(dev);
+ head = fib_nh_head(dev);
hlist_for_each_entry_rcu(nh, head, nh_hash) {
- if (nh->fib_nh_dev == dev &&
- nh->fib_nh_gw4 == gw &&
+ DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
+ if (nh->fib_nh_gw4 == gw &&
!(nh->fib_nh_flags & RTNH_F_DEAD)) {
return 0;
}
@@ -1595,7 +1588,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
if (!nexthop_nh->fib_nh_dev)
continue;
- head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
+ head = fib_nh_head(nexthop_nh->fib_nh_dev);
hlist_add_head_rcu(&nexthop_nh->nh_hash, head);
} endfor_nexthops(fi)
}
@@ -1948,12 +1941,12 @@ void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
{
- struct hlist_head *head = fib_info_devhash_bucket(dev);
+ struct hlist_head *head = fib_nh_head(dev);
struct fib_nh *nh;
hlist_for_each_entry(nh, head, nh_hash) {
- if (nh->fib_nh_dev == dev)
- fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
+ DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
+ fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
}
}
@@ -1967,7 +1960,7 @@ void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
*/
int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
{
- struct hlist_head *head = fib_info_devhash_bucket(dev);
+ struct hlist_head *head = fib_nh_head(dev);
struct fib_info *prev_fi = NULL;
int scope = RT_SCOPE_NOWHERE;
struct fib_nh *nh;
@@ -1981,7 +1974,8 @@ int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
int dead;
BUG_ON(!fi->fib_nhs);
- if (nh->fib_nh_dev != dev || fi == prev_fi)
+ DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
+ if (fi == prev_fi)
continue;
prev_fi = fi;
dead = 0;
@@ -2131,7 +2125,7 @@ int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
}
prev_fi = NULL;
- head = fib_info_devhash_bucket(dev);
+ head = fib_nh_head(dev);
ret = 0;
hlist_for_each_entry(nh, head, nh_hash) {
@@ -2139,7 +2133,8 @@ int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
int alive;
BUG_ON(!fi->fib_nhs);
- if (nh->fib_nh_dev != dev || fi == prev_fi)
+ DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
+ if (fi == prev_fi)
continue;
prev_fi = fi;
--
2.47.0.rc0.187.ge670bccf7e-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread* Re: [PATCH net-next 4/4] ipv4: remove fib_info_devhash[]
2024-10-04 13:47 ` [PATCH net-next 4/4] ipv4: remove fib_info_devhash[] Eric Dumazet
@ 2024-10-04 22:45 ` Kuniyuki Iwashima
2024-10-07 14:08 ` Simon Horman
1 sibling, 0 replies; 13+ messages in thread
From: Kuniyuki Iwashima @ 2024-10-04 22:45 UTC (permalink / raw)
To: edumazet
Cc: alexandre.ferrieux, davem, dsahern, eric.dumazet, kuba, kuniyu,
netdev, pabeni
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 4 Oct 2024 13:47:20 +0000
> Upcoming per-netns RTNL conversion needs to get rid
> of shared hash tables.
>
> fib_info_devhash[] is one of them.
>
> It is unclear why we used a hash table, because
> a single hlist_head per net device was cheaper and scalable.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Thanks!
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH net-next 4/4] ipv4: remove fib_info_devhash[]
2024-10-04 13:47 ` [PATCH net-next 4/4] ipv4: remove fib_info_devhash[] Eric Dumazet
2024-10-04 22:45 ` Kuniyuki Iwashima
@ 2024-10-07 14:08 ` Simon Horman
2024-10-07 14:13 ` Eric Dumazet
1 sibling, 1 reply; 13+ messages in thread
From: Simon Horman @ 2024-10-07 14:08 UTC (permalink / raw)
To: Eric Dumazet
Cc: David S. Miller, Jakub Kicinski, Paolo Abeni, David Ahern,
Kuniyuki Iwashima, Alexandre Ferrieux, netdev, eric.dumazet
On Fri, Oct 04, 2024 at 01:47:20PM +0000, Eric Dumazet wrote:
> Upcoming per-netns RTNL conversion needs to get rid
> of shared hash tables.
>
> fib_info_devhash[] is one of them.
>
> It is unclear why we used a hash table, because
> a single hlist_head per net device was cheaper and scalable.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> .../networking/net_cachelines/net_device.rst | 1 +
> include/linux/netdevice.h | 2 ++
> net/ipv4/fib_semantics.c | 35 ++++++++-----------
> 3 files changed, 18 insertions(+), 20 deletions(-)
>
> diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
> index 22b07c814f4a4575d255fdf472d07c549536e543..a8e2a7ce0383343464800be8db31aeddd791f086 100644
> --- a/Documentation/networking/net_cachelines/net_device.rst
> +++ b/Documentation/networking/net_cachelines/net_device.rst
> @@ -83,6 +83,7 @@ unsigned_int allmulti
> bool uc_promisc
> unsigned_char nested_level
> struct_in_device* ip_ptr read_mostly read_mostly __in_dev_get
> +struct hlist_head fib_nh_head
> struct_inet6_dev* ip6_ptr read_mostly read_mostly __in6_dev_get
> struct_vlan_info* vlan_info
> struct_dsa_port* dsa_ptr
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 4d20c776a4ff3d0e881b8d9b99901edb35f66da2..cda20a3fe1adf54c1e6df5b5a8882ef7830e1b46 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -2209,6 +2209,8 @@ struct net_device {
>
> /* Protocol-specific pointers */
> struct in_device __rcu *ip_ptr;
> + struct hlist_head fib_nh_head;
> +
> #if IS_ENABLED(CONFIG_VLAN_8021Q)
> struct vlan_info __rcu *vlan_info;
> #endif
Hi Eric,
A minor nit from my side: Kernel-doc should be updated for this new field.
...
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH net-next 4/4] ipv4: remove fib_info_devhash[]
2024-10-07 14:08 ` Simon Horman
@ 2024-10-07 14:13 ` Eric Dumazet
0 siblings, 0 replies; 13+ messages in thread
From: Eric Dumazet @ 2024-10-07 14:13 UTC (permalink / raw)
To: Simon Horman
Cc: David S. Miller, Jakub Kicinski, Paolo Abeni, David Ahern,
Kuniyuki Iwashima, Alexandre Ferrieux, netdev, eric.dumazet
On Mon, Oct 7, 2024 at 4:08 PM Simon Horman <horms@kernel.org> wrote:
> Hi Eric,
>
> A minor nit from my side: Kernel-doc should be updated for this new field.
Oh well, do we still carry kdoc for this gigantic structure ?
So many minor details adding a lot of noise for no benefit :/
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL
2024-10-04 13:47 [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL Eric Dumazet
` (3 preceding siblings ...)
2024-10-04 13:47 ` [PATCH net-next 4/4] ipv4: remove fib_info_devhash[] Eric Dumazet
@ 2024-10-04 14:35 ` David Ahern
2024-10-08 0:10 ` patchwork-bot+netdevbpf
5 siblings, 0 replies; 13+ messages in thread
From: David Ahern @ 2024-10-04 14:35 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: Kuniyuki Iwashima, Alexandre Ferrieux, netdev, eric.dumazet
On 10/4/24 7:47 AM, Eric Dumazet wrote:
> Inspired by 9b8ca04854fd ("ipv4: avoid quadratic behavior in
> FIB insertion of common address") and per-netns RTNL conversion
> started by Kuniyuki this week.
>
> ip_fib_check_default() can use RCU instead of a shared spinlock.
>
> fib_info_lock can be removed, RTNL is already used.
>
> fib_info_devhash[] can be removed in favor of a single
> pointer in net_device.
>
> Eric Dumazet (4):
> ipv4: remove fib_devindex_hashfn()
> ipv4: use rcu in ip_fib_check_default()
> ipv4: remove fib_info_lock
> ipv4: remove fib_info_devhash[]
>
> .../networking/net_cachelines/net_device.rst | 1 +
> include/linux/netdevice.h | 2 +
> net/ipv4/fib_semantics.c | 77 +++++++------------
> 3 files changed, 31 insertions(+), 49 deletions(-)
>
For the set:
Reviewed-by: David Ahern <dsahern@kernel.org>
^ permalink raw reply [flat|nested] 13+ messages in thread* Re: [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL
2024-10-04 13:47 [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL Eric Dumazet
` (4 preceding siblings ...)
2024-10-04 14:35 ` [PATCH net-next 0/4] ipv4: preliminary work for per-netns RTNL David Ahern
@ 2024-10-08 0:10 ` patchwork-bot+netdevbpf
5 siblings, 0 replies; 13+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-10-08 0:10 UTC (permalink / raw)
To: Eric Dumazet
Cc: davem, kuba, pabeni, dsahern, kuniyu, alexandre.ferrieux, netdev,
eric.dumazet
Hello:
This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Fri, 4 Oct 2024 13:47:16 +0000 you wrote:
> Inspired by 9b8ca04854fd ("ipv4: avoid quadratic behavior in
> FIB insertion of common address") and per-netns RTNL conversion
> started by Kuniyuki this week.
>
> ip_fib_check_default() can use RCU instead of a shared spinlock.
>
> fib_info_lock can be removed, RTNL is already used.
>
> [...]
Here is the summary with links:
- [net-next,1/4] ipv4: remove fib_devindex_hashfn()
https://git.kernel.org/netdev/net-next/c/8a0f62fdeb9e
- [net-next,2/4] ipv4: use rcu in ip_fib_check_default()
https://git.kernel.org/netdev/net-next/c/fc38b28365e5
- [net-next,3/4] ipv4: remove fib_info_lock
https://git.kernel.org/netdev/net-next/c/143ca845ec0c
- [net-next,4/4] ipv4: remove fib_info_devhash[]
(no matching commit)
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 13+ messages in thread